Ingredients:

  • 2 1/4 cups (281 g) all-purpose flour, plus more for dusting
  • 1 teaspoon baking powder
  • 1/2 teaspoon salt
  • 1 cup (226g) unsalted butter, softened
  • 3/4 cup (150g) granulated sugar
  • 1 large egg
  • 1 teaspoon vanilla extract
  • 2 tablespoons unsweetened cocoa powder
  • 1 tablespoon milk

Instructions:

  1. Whisk together flour, baking powder, and salt. Cream together butter and sugar until light and fluffy. Beat in egg and vanilla. Gradually add the dry ingredients to the wet ingredients until just combined.
  2. Divide the dough in half. In one bowl, mix in the cocoa powder and milk until evenly combined.
  3. Flatten each dough half into a disc, wrap in plastic wrap, and refrigerate for at least 1 hour.
  4. On a lightly floured surface, roll each dough disc into a 12x8 inch rectangle. Place the chocolate dough rectangle on top of the vanilla dough rectangle.
  5. Starting from one of the long sides, tightly roll the dough into a log. Wrap tightly in plastic wrap and refrigerate for at least 30 minutes (or up to 2 hours).
  6. Preheat oven to 375°F (190°C). Line baking sheets with parchment paper. Cut the dough log into 1/4-inch thick slices. Place cookies on the prepared baking sheets, leaving about 1 inch between cookies.
  7. Bake for 8-10 minutes, or until the edges are lightly golden.
  8. Let the cookies cool on the baking sheets for a few minutes before transferring them to a wire rack to cool completely.